Video conferencing has recently been evolving into the realm of lightweight portable computing devices such as mobile phones and tablet computers. Mobile phones, for example, which only carried voice signals in past years, are now capable of capturing, sending and receiving streams of video frames in real time. Video conferencing between lightweight portable computing devices such as mobile phones and tablet computers is constrained by the limited computational capacity and computational speed of the lightweight devices, by the need to conserve their battery life, and by bandwidth restrictions on networks like 3G and 4G mobile device networks that transmit signals between the lightweight devices. Similar constraints also still apply to larger, more powerful computing devices such as geographically remote computer work stations which conduct video conferencing over high-speed networks. However, the constraints are more pronounced in the world of mobile computing devices.
Rapid, real-time exchange of clear images in video streams passing from one lightweight media device to another requires the sending device to quickly encode information for each sent video frame so that a decoding mechanism can reconstruct an accurate representation of the sent video frame. The encodings for the sequence of video frames must be compact enough that they can flow speedily through the network pipe connecting the sending and receiving devices, yet they must also convey sufficient data to facilitate reconstructing accurate renderings of the sequence of video frames for display on a receiving device. A judicious balance must be struck between the degree of video compression occurring on the sending device and the accuracy of the result, and between the size of the encoding and the speed of its transmission across the network.